Fighting Fires Involving Toxic and Irritant Gases

Fighting Fires Involving Toxic and Irritant Gases

Each Chemical Fire Has Its Own Characteristics and Hazards—A Knowledge of Effects of Such Cases is Useful


THE subject of fighting fires where chemicals are involved is one of such magnitude that we will attempt to discuss only one phase of it—that of coping with fires or other emergencies wherein toxic, irritant or otherwise dangerous gases are involved. This is approached from the viewpoint of a working Fire Chief, rather than from that of a chemist or an engineer. To present facts and avoid theory, in the following paragraphs, we will simply recount a number of cases selected at random from the actual and personal experience of the writer, for whatever value any lessons to be derived from these may have.

Types of Gases Mentioned

The following gases will be mentioned, and incidents related where they were encountered: Ammonia, benzol, bromine, carbon monoxide, carbon tetrachloride, chlorine, hydrogen sulphide, nitric oxide, sulphur dioxide, smoke. It is not contended that the methods employed were the best and most effective that might have been used, but they were available at the time of emergency and actually did meet the situation.

The following hazards may be present where tanks or containers holding ammonia gas under pressure are involved in or exposed to a fire: a. The presence of ammonia gas from leaking or broken pipes; b. the possibility of ammonia tanks exploding under high pressure from heat, as this gas expands rapidly when hot; or c. the possibility of explosion from a mixture of ammonia fumes and air.

Several types of filter masks are of value for protection against ammonia fumes, these generally employing activated charcoal, impregnated with copper sulphate as a reagent, although in severe concentrations air hose masks or self contained breathing apparatus must be used. Men entering this gas should keep clothing fastened around their necks and tie their trouser legs at the bottom, as sensitive parts of the body will be injured.

Walter W. Stephen

Leaking Ammonia Gas

The following is an example: A plant department was called to a section of a chemical plant where ammoniacal salts were manufactured. Ammonia gas in large amounts was escaping from a defective valve in a large pressure tank and was flooding the building. There was considerable hazard that an explosive mixture in the air might be reached.

The officer in charge, wearing an All-Service gas mask, entered the building, after it had been ventilated as far as possible, with a 1 1/2-inch hose line, equipped with controlling nozzle. This nozzle, when partly open, threw a sheet of spray, although it was not of the fog type that has been since developed. This spray was partly effective in sweeping down fumes and absorbing them, where they were coming from the tank. The valve on the pipe line from tank was closed and the escape of fumes ceased. The officer was blistered by fumes on the sensitive parts of his body.

Ventilation as much as possible and the use of fog or water spray are advisable measures in buildings involved with ammonia gas.

Fire from Ignited Benzol Pipe Line

A fire that occurred when a benzol pipe line began leaking near a gas burner, involved part of a coal tar by-product plant building. The plant department at that time had no foam apparatus and fought the fire by using several streams from 2 1/2-inch hose lines. These prevented severe damage to the building, confined the fire to a limited area and finally extinguished it, when most of the free benzol was burned out.

At least half a dozen pipemen were made dizzy and sick from benzol fumes that were not concentrated enough to burn or explode.

Two pipemen, wearing All-Service gas masks, worked throughout fire in places of the most severe exposure with no ill effects.

Bromine Fumes Constitute a Fire Hazard

A plant department was called to a plant laboratory building. A packing case with the top open, filled with excelsior and containing several bottles of liquid bromine, was on fire, having been ignited by sodium peroxide powder spilled on the excelsior, which had been set off by water spray from a sink. These bottles had been exploded. Building was full of intense, brownish bromine fumes. Windows and doors were opened. Officer in charge wearing All-Service gas mask, entered with a one-inch hose line, extinguished fire and washed out remaining bromine, after dragging packing case from building.

Carbon Monoxide Dangers

To fully discuss this gas would take all the time that might be occupied by reading several manuscripts. It is responsible, far and above the sum of all the other gases on earth, for discomfort and injury to firemen in their occupation of putting out fires. It is colorless, insidious and deadly in minute concentration. It is to be found at many fires, often when there is not so much smoke and men are not expecting to encounter it. In combination with other partly oxidized products of combustion, it will mushroom in the upper part of a burning building and, unless vented from above, will flash off with an explosion and involve large floor or loft areas.

Although theoretically lighter than air, it will be dragged down by other gases and act as though it were heavier than air.

All-Service gas masks or other filter type masks using a chemical known as “Hopcalite” will afford some measure of protection from carbon monoxide, if the concentration is not too great, but the following experience indicates that a positive supply of air is the only dependable safeguard. This occurred recently:

A Fire Involving Carbon Monoxide

A plant department was called to plant building wherein carbon monoxide gas was escaping and it was necessary to enter and remedy this.

A man wearing an All-Service mask entered, became dizzy and coming out, had to be revived with an oxygen-carbon dioxide mixture from an inhalator. As it was thought this happened because of an over used gas mask canister, another man, wearing a new mask with a new canister in good order, entered building. He became sick in a very short time and had to be treated with the inhalator.

A third man wearing an M. S. A. hose mask supplied by an air blower then went in and was able to work with no discomfort, although somewhat hampered by the air hose line.

Knowledge of Artificial Respiration Necessary

We would say that a knowledge of artificial respiration is something every fireman should have. To qualify this statement we might mention that the writer has, during the past, resuscitated no less than six persons who were given up for dead after carbon monoxide exposure, and who would have been dead, had not some one with the necessary training been present. He has also assisted in the revival of a number of other cases.

The use of an inhalator in treating headaches from ordinary smoke exposure, most of which are caused by carbon monoxide, is a procedure that will add much to the comfort of the members of any department. This inhalator, briefly, consists of a facepiece connected to a portable tank or tanks, containing a mixture of 93 per cent oxygen and seven per cent carbon dioxide.

Effects of Carbon Tetrachloride Fumes

Fumes from carbon tetrachloride and other gases from the decomposition by heat of this chemical will, in a closely confined place, cause discomfort or injury to persons exposed. A plant department, called to a fire in a large wooden building, containing drums of calcium carbide, found fire burning in wooden floor, under a large pile of loaded drums.

As this was going on in a wooden building of large size and area, in which it was not possible to use water, it will be seen that a very grave situation existed. Officer in charge, arriving with first piece of apparatus, found that two employees, who had been fighting fire with one quart pump type and five gallon pump type carbon tetrachloride extinguishers in a narrow area between piles of drums, had been driven out by fumes from the fluid they were using and were sick, with saliva running from their mouths.

Officer entered place with carbon tetrachloride extinguisher and wearing All-Service gas mask. He was able to check the fire with this extinguisher, until a second piece of plant fire department apparatus arrived. with carbon dioxide equipment.

Stream of carbon dioxide “snow” shot under piles of drums and between drums reached fire and effectually snuffed it out. Piles were laboriously moved and smouldering places in boards overhauled.

Chlorine Gas

Members of a plant department were returning with apparatus to quarters after a fire, and while passing a one story laboratory building, were surprised to see occupants of building running front doors and jumping from windows, followed by clouds of yellowish chlorine gas.

Officer in charge, wearing AllService gas mask, entered building and found that a large portable cylinder of chlorine gas under high pressure had the valve broken. He tied a rope to the tank and dragged it out. He was made sick by gas and had the color bleached out of the socks he was wearing at the time.

The effect of chlorine is that it is a severe irritant to the throat. It will not ordinarily cause oedema, or blistering of the inner respiratory organs, and for this reason men subject to it and not asphyxiated or killed by the initial dose, will recover if they are still able to breathe, and will suffer no delayed effect, such as that produced by nitric oxide gas.

In each case severe coughing will take place, and must be relieved. The following mixture has been found very effective for this, after trying many remedies:

The All-Service type gas mask is effective in concentrations ordinarily encountered. The layers of activated charcoal, caustic and the material known as “hopcalite” will neutralize chlorine.

Hydrogen Sulphide Causes Mental Paralysis

Hydrogen sulphide is found in some chemical plants and the petroleum industry. It is flammable and, in some mixtures with air, is explosive. It will produce temporary mental paralysis, as well as physical coma. On one occasion during the past, the writer, after entering a building and carrying out a 180 pound man, who had been overcome by this gas, carried him a distance of nearly two city blocks to the plant hospital, and to this day cannot remember the occasion, due to gas encountered in entering this building. No gas mask was used at the time.

Chicago Fire Losses Drop to Low Level Education is credited with the Chicago reduction in fire losses, which last year was $5,700,000, the second lowest annual figure in eleven years. The extent of the fire losses is shown in a novel graph.

A plant department was called to a fire at a hydrogen sulphide generator. This gas, escaping from a generator tank, from which a pressure relief diaphram had been blown, was burning with a peculiar flame. Tank was flooded with carbon dioxide gas from extinguishers carried on plant apparatus and the fire extinguished.

Deadly Characteristics of Nitric Oxide

The hazardous and deadly characteristics of this gas cannot be exaggerated. It is formed by the decomposition of nitric acid and nitrates, many of which exist in the form of materials, such as “celluloid,” or other forms of nitro-cellulose, that arc encountered in many occupancies.

This gas exists in an orange or brownish yellow form. Tt is advisable to enter this only with masks using a positive air supply, although the filter type mask will in moderate concentrations neutralize it. The danger lies in the fact that men exposed to it will often not know they are affected until there is no hope of medical aid for them. Many fatalities have occurred wherein men exposed to this gas went on about their business for several hours before it became apparent that there was anything the matter with them. It produces a delayed effect, causing oedema, or blistering of the lungs, literally drowning the person affected.

Ammonia, if breathed immediately after exposure, is a beneficial agent. The fact exists that on one occasion a patient who had apparently a severe dose, and who was thus treated, recovered in a surprising manner.

Ventilation and air line or self breathing masks should be employed, if it is necessary to enter a building containing this gas.

A plant department was called to a laboratory building, where a fire had occurred in a potassium nitrate mixing kettle. Building was involved in a cloud of orange hued fumes, so dense it could hardly be seen. Doors were opened and windows opened with pike poles. This partly cleared building and pipemen. wearing hose masks supplied by a blower, entered far enough to locate the fire and put it out with a 2 1/2-inch line from a foam generator.

Sulphur Dioxide Irritates Eyes and Respiratory Organs

Plant department was called to a fire in a sulphur bin in a small building. This material was burning with an almost invisible flame and was emitting dense clouds of sulphur dioxide, which irritated and blinded the eyes of persons contacting it, as well as affecting their respiratory systems.

A forty gallon soda-acid engine was used on the fire, without very much effect. Two men, wearing hose masks, entered the building and extinguished the fire by using six 18pound portable carbon dioxide extinguishers, two at a time.

Sulphur dioxide has certain toxic qualities, but in moderate concentrations the All-Service mask will afford protection from it. Being a product of the combustion of sulphur, it will not burn.

Fighting Smoky Fires

This, in itself, is a subject as extensive as the entire field of fire fighting.

The smoke encountered, ordinarily, at a fire, consists of a mixture of oxygen, nitrogen, carbon dioxide, often some carbon monoxide, finely divided carbon and a miscellaneous assortment of products from the combustion of wood and other materials.

The writer will attempt only to say that the All-Service gas mask, provided there is enough oxygen present to sustain life, will enable men to work in ordinary smoke, where heat and flame are not too great and where man may be able to see well enough to accomplish anything. This happened two years ago:

A plant department was called on a third alarm assignment to a down town district, where parts of the basement. the rear of each floor and the loft of a three story brick and wood joist bank building were involved by a fire which lines, operated by four engine companies and a truck company, were unable to reach because of intense smoke that made it hard to even see the building.

By the use of several All-Service masks, carried on plant apparatus, it was possible to reach and open windows for ventilation and to open the roof in the rear of the building, directly over where the fire was coming up and to open the top of the elevator shaft. When this ventilation was effected, it was possible to reach and finally knock out the fire in the basement, all the floors and the loft, with a loss of less than 20 per cent of values involved.

In using masks in smoke, it is not advisable for any man to go in alone, or for men to go in without some method of finding their way out.

In working where fire streams are operated the eyepieces will at once become covered with water and vision thus greatly obscured. Men can do continued hard work while wearing a mask only by training and experience. Often because of the inconvenience of wearing masks men will prefer to “go in and take it” without them.

General Suggestions for Fighting Chemical Fires

The following information is offered for whatever it may be worth. It is possible to equip the All-Service mask or other filter type masks with a facepiece that extends only over the nose and mouth, which eliminates the visual obscurity caused by wet eye pieces and seems to do away to some extent with the unpleasant “shut in” feeling that attends the wearing of a mask, although goggles may be used, if it is necessary to protect the eyes. The writer has used this type of face piece and submits this as the result of actual experience.

Finally, for the treatment of men affected by any of the above kinds of gas, until medical aid be secured there is advised quiet, warmth and fresh air.

If available oxygen, or a mixture of oxygen with a small per cent of carbon dioxide, should be administered, and, of course, artificial respiration given if this be necessary.

(From a paper read before the annual convention of the Southeastern Association of Fire Chiefs, at Knoxville, Tenn.)

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